After months of tantalizing beta teases, Apple's latest OS X refresher is now available for download in the Mac App Store. The 4.05GB update will cost you an entirely reasonable $20, and features improvements like a new Notification Center, Twitter baked in throughout, and dictation that's pleasantly—and surprisingly—decent.

You can check out our full review here. But twenty bucks for a faster, smoother, more feature-filled Lion? Seems pretty worth it.